Civil Engineering Reference
In-Depth Information
To accommodate the plane strain limitations of the finite element model, the
cross sectional properties of the structural elements were determined by dividing
the column and beam properties by the tributary width of the frame selected as 10
feet, and by utilizing the equivalent area and moment of inertia per foot of length
of the floor slab. Given that gravity loads on the structural elements are not of
concern, this method of resolving the cross sectional properties of the rigid frame
elements allows an adequate modeling of the lateral stiffness of the rigid frame
under plane strain conditions.
The stages of construction were incorporated in the analysis to simulate an
initial stage where a structural frame was first completed and later received
backfill soil in several stages. After the addition of the backfill soil, an increase in
temperature of 60ºF was applied to the structure, followed by a temperature
decrease of 100ºF and subsequent cycles of 100ºF increase and decrease in
temperature. The displacement of the structures, stresses in the structural
Table 9.1
Finite Element Analysis Parameters
Parameter
Variation
Number of Bays for Structural Frames, n
1, 3, 6, 10, 15 and 20
Bay Lengths for Structural Frames, L
b
(ft)
10 and 20
Number of Stories for Structural Frames, s
2, 3, 4, 5
Story Height, h (ft)
10
Structural Beam Properties
Cross Sectional Area, A
b
(in
2
)
144
Moment of Inertia, I
b
(in
4
)
2073 and 1036
Structural Column Properties
Cross Sectional Area, A
c
(in
2
)
144 and 432
Moment of Inertia, I
c
(in
4
)
2073 and 41460
Structural Wall Properties
Cross Sectional Area, A
w
(in
2
/ft)
144
Moment of Inertia, I
w
(in
4
/ft)
2073
Modulus of Elasticity of Structural Members, E
s
(ksi)
3150
0.25
Poisson Ratio of Structural Members, ν
s
Density of Structural Members,
γ
s
(pcf)
150
Backfill Soil Properties
Internal Friction Angle,
φ
(Degrees)
30
Dilatancy Angle,
ψ
(Degrees)
0
Cohesion, c (psi)
0
Modulus of Elasticity, E (ksi)
41500
Density,
γ
(pcf)
100
Strength Reduction for Interfaces
0.75
